Res 2024-045 approving the 2024 City of San Marcos Hazards Mitigation Action Plan (“HMAP”)

Home Browse Search

SECTION 4: RISK OVERVIEW The accumulation of water within a body of water, which results in the overflow of excess water onto adjacent lands, usually floodplains. The floodplain is the land adjoining the channel of Flood a river, stream, ocean, lake, or other watercourse or water body that is susceptible to flooding. Most floods fall into the following three categories: riverine flooding, coastal flooding, and shallow flooding. • Expansive soils are soils and soft rock that tend to swell or shrink due to changes in moisture content. Changes in soil Expansive Soils volume present a hazard primarily to structures built on top of expansive soils. A wildfire is an uncontrolled fire burning in an area of vegetative fuels such as grasslands, brush, or woodlands. Heavier fuels with high continuity, steep slopes, high temperatures, low Wildfire humidity, low rainfall, and high winds all work to increase the risk for people and property located within wildfire hazard areas or along the urban/wildland interface. Wildfires are part of the natural management of forest ecosystems, but most are caused by human factors. An earthquake is the sudden, rapid, shaking of the earth, caused by the breaking and shifting of subterranean rock as it Earthquake releases strain that has accumulated over a long time. Initial mild shaking may strengthen and become extremely violent within seconds. Dam failure is the collapse, breach, or other failure of a dam structure resulting in downstream flooding. In the event of a Dam Failure failure, the energy of the water stored behind even a small dam is capable of causing loss of life and severe property damage if development exists downstream of the dam. Hazards that weren't considered significant and were not included in the Plan Update are located in Table 4-2, along with the evaluation process used for determining the significance of each of these hazards. Hazards not identified for inclusion at this time may be addressed during future evaluations and updates. Table 4-2. Other Hazards Deferred Coastal Erosion The planning area is not located on the coast, therefore coastal erosion does not pose a risk. City of San Marcos I Hazard Mitigation Action Plan Update 2024 1 Page 3